A method for preparing a sintering enhancer using high-iron steel slag

Abstract

The application discloses a method for preparing sintering reinforcement agent by using high-iron steel slag, and the method comprises the following steps: treating converter steel slag by means of hot sweating, hot splashing, shallow tray, air quenching and water quenching, and then performing magnetic separation to obtain magnetic separation tailing; grinding the magnetic separation tailing, and then leaching calcium and magnesium in an acid solution to obtain leaching liquid and leaching tailing; adding acid solution into the leaching tailing, stirring and reacting under the condition of 10 DEG C-50 DEG C for 1-4 hours, filtering and drying after solid-liquid layering to obtain sintering reinforcement agent masterbatch; grinding the sintering reinforcement agent masterbatch and a reinforcement control agent into powder respectively, mixing them according to the proportion to obtain a mixture with binary basicity of 1.5-3, and the mixture is the final sintering reinforcement agent. The method has the advantages of easy raw material acquisition, simple process, convenient operation, and the like, and the obtained product can be directly added into sintering raw materials, so that good sintering strength can be provided for sinter, and meanwhile, sintering burdening cost can be reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of comprehensive utilization of metallurgical resources, and particularly relates to a method for preparing a sintering reinforcing agent by using high-iron steel slag. BACKGROUND

[0002] According to the statistics of the World Steel Association, in 2023, the crude steel output of China was 1019 million tons, accounting for about 54% of the global total output. Steel slag is a solid waste inevitably produced in the steelmaking process. In 2023, more than 100 million tons of steel slag were produced in China. At present, the utilization rate of steel slag in Europe and the United States reaches 90%, while the utilization rate of steel slag in China is only 20% to 30%. Due to the low comprehensive utilization rate of steel slag in China, more than 100 million tons of steel slag are stored, occupying a large amount of space and land, and there is a risk of leaching of toxic heavy metal elements, polluting surrounding water and soil, and other ecological risks. Therefore, how to select a suitable ecological disposal method according to its characteristics and make full use of steel slag as a resource has become a major issue of concern in the metallurgical industry.

[0003] Domestic steel enterprises mainly adopt hot smothering method, hot splashing method, shallow tray method, air quenching method, water quenching method and other methods to treat steel slag, and there are few deep processing and value-added treatment. Steel slag contains a large amount of Fe, Ca and other elements, which is an ideal sintering reinforcing agent raw material. Because Fe elements in the slag are easy to combine with Ca elements to form calcium ferrite, affecting the magnetic separation recovery efficiency, leading to the existence of high Fe content in the tailings of magnetic separation. If not disposed reasonably, it will directly cause waste of resources, and also affect the application of steel slag as a cementing material in civil engineering fields. Previous studies have shown that treating steel slag with an acidic solution can selectively decompose the free calcium oxide phase in the steel slag, and the calcium-containing solution can be used to capture CO2 in metallurgical flue gas to achieve waste treatment with waste. At the same time, the stability of the treated steel slag is greatly improved, and the calcium ferrite is enriched, which is an ideal raw material for preparing a sintering reinforcing agent. Compared with other sintering reinforcing agents, valuable elements are extracted from waste materials generated from the metallurgical process and applied to the recycling process, which can realize the resource utilization of high-iron (high Fe content) steel slag and also avoid the large-scale mining of related mineral resources.

[0004] At present, the utilization of steel slag still has the following problems difficult to solve: first, the composition and components in steel slag are complex and difficult to be selectively extracted and utilized; second, the tail slag contains free CaO and MgO, and the calcium silicate is in a metastable phase after rapid cooling, resulting in poor organization stability of the tail slag; third, the tail slag is dense and hard, and has poor grindability, so the grinding cost of steel slag powder is high, reducing the utilization economy. Therefore, the use of steel slag is limited mainly due to poor organization stability and unreasonable composition. Patent CN114293010A discloses a method for preparing sintered ore by adding steel slag tailings through sintering process. The preparation of raw materials in this method needs to involve multiple materials, and the batching is difficult. Patent CN116891938A discloses a method for preparing sintered ore by using converter steel slag tailings. The application mixes iron materials with batching materials to form sintering pellets by using a pelletizer, and then obtains sintered ore through steps such as material distribution equipment and ignition sintering. However, the sintered ore cannot be directly obtained through the steps of pelletizing, distributing and sintering. Patent CN116287687A discloses a method for preparing sintered ore by using steel slag tailings after extracting CaO. The application mixes steel slag tailings after extracting CaO, fine iron ore and iron ore powder with water to form granules, and then obtains sintered material by sintering the mixed material. However, it is not stated whether the extraction of CaO will affect the strength of sintered ore and other factors. Patent CN116574901A discloses a granulation strengthening agent based on metallurgical solid waste, sintering mixture and sintering strengthening method of ultra-thick layer. The application prepares a granulation strengthening agent by using metallurgical solid waste, and then prepares a sintering mixture by using the prepared granulation strengthening agent as one of the raw materials. However, the granulation strengthening agent cannot be directly added to the sintered ore, and the finished product requirements of the granulation strengthening agent and the sintering mixture are high, which is harsh on the process requirements. SUMMARY

[0005] In order to overcome the defects of the prior art and solve the problems of steel slag tailings accumulation and application in sintering process, the application performs acid leaching treatment on the magnetic tailings after magnetic separation, mixes the silicon washed tailings with a strengthening regulator to obtain a sintering strengthening agent. The method has the characteristics of simple raw materials, simple process and easy operation, and the obtained product can be directly added to the sintering raw materials without further sintering of the sintering strengthening agent. By reducing the silicon content in the magnetic tailings, the proportion of iron components can be increased, which can provide good sintering strength for sintered ore and reduce the sintering batching cost.

[0006] In order to achieve the above-mentioned application purposes, the application provides a method for preparing a sintering strengthening agent by using high-iron steel slag, which comprises the following steps:

[0007] ①In the converter smelting production process, after the converter slag is treated by hot fumigation, hot splashing, shallow tray, air quenching, water quenching and the like, the converter slag enters the magnetic separation line for magnetic separation, and the magnetic separation tailings are obtained;

[0008] ②The magnetic separation tailings obtained in step ① are ground and then leached in an acidic solution, and the leaching liquid and leaching tailings are obtained by filtration;

[0009] ③An acidic solution is added to the leaching tailings obtained in step ②, and stirring reaction is carried out at 10-50℃ for 1-4h, and then the solid-liquid layering is carried out, and the sintering strengthening agent masterbatch is obtained by filtration and drying;

[0010] ④The sintering strengthening agent masterbatch obtained in step ③ and the strengthening control agent are ground into powder respectively, and then mixed in proportion to obtain a mixture with a binary basicity of 1.5-3, which is the final sintering strengthening agent.

[0011] The main phases of the converter slag are dicalcium silicate, metallic iron phase, free calcium oxide, calcium ferrite and ferrite, wherein the content of Fe is greater than 15%, and the main components are CaO, SiO2, FeO, MgO, Al2O3 and the like.

[0012] In the above technical solution, further, the magnetic separation tailings obtained in step ① are used as raw materials for preparing the sintering strengthening agent, and the mass fraction of the main chemical components in the raw materials is as follows: TFe: 15%-25%, CaO: 40%-60%, SiO2: 10%-20%, and MgO: 6%-10%.

[0013] Further, the acidic solution in step ② is one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, ammonium chloride, ammonium nitrate, ammonium sulfate and the like, and the pH value is 2-3, the concentration of the acidic solution is 0.5-2mol / L, the leaching reaction temperature is 10-100℃, the leaching reaction time is 0.5-4h, and the stirring rate is 150-600rpm; and the solid-liquid ratio of the magnetic separation tailings to the acidic solution is 1:5-1:40g / mL.

[0014] Further, in step ②, the obtained leaching tailings are made into cylindrical materials by using a mold, the materials are sent into a temperature raising device to observe the melting morphology characteristics of the materials, the melting point and melting speed of the leaching tailings are measured, and then it is judged whether the prepared sintering strengthening agent meets the sintering condition according to the condition. The main chemical components of the leaching tailings in step ② are as follows: TFe: 20%-40%, CaO (or other Ca compounds): 20%-30%, SiO2: 25%-35%, and MgO: 2%-6%.

[0015] Furthermore, the acidic solution system in step ③ is a solution prepared from one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, ammonium chloride, ammonium nitrate, and ammonium sulfate, with a pH value of 0.1 to 1 and a concentration of 0.5 to 1 mol / L; the solid-liquid ratio of the leaching tailings to the acidic solution is 1:5 to 1:40 g / mL, and the stirring speed is 300 to 600 rpm.

[0016] Furthermore, the strengthening regulator mentioned in step ④ is one or both of CaO reagent and SiO2 reagent. The dried strengthening agent masterbatch and strengthening regulator are ground into powders smaller than 100 mesh. The strengthening agent masterbatch and strengthening regulator are mixed in a mass ratio of 1:0.25 to 1:0.5 to form a mixture with a binary basicity (CaO / SiO2) of 1.5 to 3. The sintering strengthening agent prepared under this basicity condition can provide good sintering strength for sintered ore.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention uses steel slag tailings with high iron and calcium content to prepare a sintering strengthening agent. By reducing the silicon content in high-iron steel slag, the proportion of iron is increased, and the iron phase in the steel slag tailings is utilized to the maximum extent, which effectively improves combustion efficiency, reduces solid fuel consumption, and increases the strength of sintered ore, thereby promoting iron production and coke saving in blast furnaces.

[0019] In this technical solution, the prepared raw materials and strengthening agent are dried without adding water during the raw material preparation and formulation process, thus avoiding the influence of water on the sintering strengthening agent. The converter steel slag after magnetic separation is acid-leached, and after silicon washing, it is mixed with the strengthening agent to obtain the sintering strengthening agent. This method features simple raw materials, a simple process, and convenient operation. Furthermore, the obtained sintering strengthening agent can be directly added to the sintering raw materials without further sintering. This provides good sintering strength for the sintered ore while reducing sintering batching costs, solving the problems of steel slag tailings accumulation and its application in the sintering process. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of the method for preparing sintering strengthening agent using high-speed railway steel slag according to the present invention;

[0021] Figure 2 The image shown is the XRD pattern of the magnetic separation tailings described in step ① of Example 1.

[0022] Figure 3 The image shown is the XRD pattern of the leaching tailings described in step ② of Example 1. Detailed Implementation

[0023] To more clearly present the technical features and beneficial effects of the present invention, the following embodiments and accompanying drawings will be used for detailed explanation. Those skilled in the art should understand that the following embodiments are for illustrative purposes only and are not intended to limit the invention in any way.

[0024] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents, materials, instruments and equipment mentioned are all commercially available unless otherwise specified.

[0025] A method for preparing a sintering strengthening agent using high-speed railway steel slag, the method comprising the following steps:

[0026] ① In the converter smelting production process, after the converter slag is discharged, the converter steel slag is treated by hot quenching, hot pouring, shallow pan quenching, air quenching, water quenching, etc., and then the converter slag enters the magnetic separation line for magnetic separation to obtain magnetic separation tailings; the main chemical components of the magnetic separation tailings are TFe: 15%~25%, CaO: 40%~60%, SiO2: 10%~20%, MgO: 6%~10%.

[0027] ② The magnetic separation tailings obtained in step ① are ground and then leached in an acidic solution. The leaching is then filtered to obtain a leachate and leached tailings. The solid-liquid ratio of the magnetic separation tailings to the acidic solution is 1:5 to 1:40 g / mL. The leaching temperature is 10℃ to 100℃, the reaction time is 0.5 to 4 h, and the stirring speed is 150 to 600 rpm. The acidic solution in step ② is a solution prepared from one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, ammonium chloride, ammonium nitrate, and ammonium sulfate, with a concentration of 0.5 to 2 mol / L and a pH value of 2 to 3. The main chemical components of the leached tailings in step ② are: TFe: 20% to 40%, CaO: 20% to 30%, SiO2: 25% to 35%, and MgO: 2% to 6%.

[0028] ③ Add an acidic solution to the leaching tailings obtained in step ②, stir and react at 10℃~50℃ for 1~4h, filter and dry after solid-liquid separation to obtain sintering strengthening agent masterbatch; the acidic solution in step ③ is a solution prepared from one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, ammonium chloride, ammonium nitrate and ammonium sulfate, with a pH value of 0.1~1 and a concentration of 0.5~1mol / L; the solid-liquid ratio of the leaching tailings to the acidic solution in step ③ is 1:5~1:40g / mL, and the stirring speed is 300~600rpm.

[0029] ④ Grind the sintering strengthening agent masterbatch and strengthening regulator obtained in step ③ into powder, mix them in proportion, and prepare a mixture with a binary basicity of 1.5 to 3, which is the final sintering strengthening agent. The strengthening regulator mentioned in step ④ is one or both of CaO reagent and SiO2 reagent. Grind the dried strengthening agent masterbatch and strengthening regulator into powder of less than 100 mesh, and mix them in a mass ratio of 1:0.25 to 1:0.5 to prepare a mixture.

[0030] Any aspects not described in the following embodiments are the same as those described in the specific embodiments above.

[0031] Example 1

[0032] A method for preparing sintering strengthening agents using high-speed railway steel slag, the specific process flow is as follows:

[0033] ① In the converter smelting process, after the converter slag is discharged, it is treated by hot quenching and hot pouring, and then enters a magnetic separation line for magnetic separation to obtain magnetic separation tailings; the main chemical components of the magnetic separation tailings are TFe: 20%, CaO: 50%, SiO2: 15%, MgO: 9% by mass fraction; the XRD pattern of the magnetic separation tailings is as follows. Figure 2 As shown, by Figure 2 It can be seen that the iron oxide phase and the calcium silicate phase are the main phases.

[0034] ② Grind the magnetic separation tailings obtained in step ① to a particle size of less than 100 mesh. Place the magnetic separation tailings in a 1 mol / L acidic solution (acetic acid solution), wherein the solid-liquid ratio of the magnetic separation tailings to the acetic acid solution is 1:5 g / mL, the reaction temperature is 20℃, the reaction time is 2 h, and the stirring speed is 300 rpm. After filtration, leachate and leaching tailings are obtained. The XRD pattern of the leaching tailings obtained in step ② is shown below. Figure 3 As shown, by Figure 3 It can be seen that the iron oxide phase is still the main phase, but the calcium silicate phase is significantly reduced, which proves that selective leaching of calcium has been achieved and the proportion of iron has been increased.

[0035] The main chemical components of the leaching tailings in step ② are as follows: TFe: 29%, CaO: 24%, SiO2: 29%, and MgO: 2%.

[0036] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe their melting morphology. The measured melting point was 1201℃.

[0037] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe the melting morphology. The melting rate was measured to be 106 s.

[0038] ③ Add an acidic solution (hydrochloric acid solution) to the leaching tailings obtained in step ②. The concentration of the hydrochloric acid solution is 1 mol / L, and the solid-liquid ratio of the leaching tailings to the hydrochloric acid solution is 1:20 g / mL. The reaction temperature is 20℃, the reaction time is 2h, and the stirring speed is 300 rpm. After the solid and liquid layers separate, filter and dry to obtain the sintering strengthening agent masterbatch.

[0039] ④ The dried reinforcing agent masterbatch (iron ore powder) and reinforcing regulator (CaO) reagent obtained in step ③ are ground into powders smaller than 100 mesh. The iron ore powder and CaO reagent are then mixed in a mass ratio of 1:0.38 to form a binary mixture with a basicity of 2.0, ultimately yielding the sintering reinforcing agent. The final sintering reinforcing agent and the compositional mass fraction of the magnetic separation tailings obtained in Example 1 are shown in Table 1. As can be seen from Table 1, this process ultimately increases the proportion of the Fe component, and the final product, the sintering reinforcing agent, can provide good sintering strength for the sintered ore. Furthermore, the parameters in Example 1 show superior performance.

[0040] Example 2

[0041] A method for preparing sintering strengthening agents using high-speed railway steel slag, the specific process flow is as follows:

[0042] ① In the converter smelting production process, after the converter slag is discharged, the converter slag is treated by hot quenching and hot pouring, and then the converter slag enters the magnetic separation line for magnetic separation to obtain magnetic separation tailings; the main chemical components of the magnetic separation tailings are TFe: 20%, CaO: 50%, SiO2: 15%, MgO: 9%.

[0043] ② Grind the magnetic separation tailings obtained in step ① to make the particle size less than 100 mesh. Place the magnetic separation tailings in an acidic solution (acetic acid solution) with a concentration of 1 mol / L, wherein the solid-liquid ratio of the magnetic separation tailings to the acetic acid solution is 1:5 g / mL, the reaction temperature is 20℃, the reaction time is 2h, and the stirring speed is 300 rpm. After filtration, leachate and leaching tailings are obtained. The main chemical components of the leaching tailings are TFe: 27%, CaO: 25%, SiO2: 30%, and MgO: 3%.

[0044] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe their melting morphology. The measured melting point was 1204℃.

[0045] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe the melting morphology. The melting rate was measured to be 115 s.

[0046] ③ Add an acidic solution (hydrochloric acid solution) to the leaching tailings obtained in step ②. The concentration of the hydrochloric acid solution is 1 mol / L, and the solid-liquid ratio of the leaching tailings to the hydrochloric acid solution is 1:20 g / mL. The reaction temperature is 20℃, the reaction time is 2h, the stirring speed is 300 rpm, and the mixed solution reacts for a period of time. After the solid and liquid layers separate, filter and dry to obtain the sintering strengthening agent masterbatch.

[0047] ④ The dried reinforcing agent masterbatch (iron ore powder) and reinforcing regulator (CaO) obtained in step ③ are ground into powders smaller than 100 mesh. The iron ore powder and CaO reagent are mixed in a mass ratio of 1:0.38 to form a binary basicity mixture of 2.0, and the sintering reinforcing agent is finally obtained. The mass fraction of the sintering reinforcing agent finally obtained in Example 2 is shown in Table 1.

[0048] Example 3

[0049] A method for preparing sintering strengthening agents using high-speed railway steel slag, the specific process flow is as follows:

[0050] ① In the converter smelting production process, after the converter slag is discharged, the converter steel slag is treated by hot quenching and hot pouring. The converter slag then enters the magnetic separation line for magnetic separation to obtain magnetic separation tailings. The main chemical components of the magnetic separation tailings are TFe: 20%, CaO: 50%, SiO2: 15%, and MgO: 9%.

[0051] ② Grind the magnetic separation tailings obtained in step ① to make the particle size less than 100 mesh. Place the magnetic separation tailings in an acidic solution (acetic acid solution) with a concentration of 2 mol / L, wherein the solid-liquid ratio of the magnetic separation tailings to the acetic acid solution is 1:5 g / mL, the reaction temperature is 20℃, the reaction time is 2h, and the stirring speed is 300 rpm. After filtration, leachate and leaching tailings are obtained. The main chemical components of the leaching tailings are TFe: 28%, CaO: 25%, SiO2: 28%, and MgO: 4% by mass.

[0052] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe their melting morphology. The measured melting point was 1205℃.

[0053] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe the melting morphology. The melting rate was measured to be 112 s.

[0054] ③ Add an acidic solution (hydrochloric acid solution) to the leaching tailings obtained in step ②. The concentration of the hydrochloric acid solution is 1 mol / L, and the solid-liquid ratio of the leaching tailings to the hydrochloric acid solution is 1:20 g / mL. The reaction temperature is 20℃, the reaction time is 2h, the stirring speed is 300 rpm, and the mixed solution reacts for a period of time. After the solid and liquid layers separate, filter and dry to obtain the sintering strengthening agent masterbatch.

[0055] ④ The dried reinforcing agent masterbatch (iron ore powder) and reinforcing regulator (CaO) obtained in step ③ are ground into powders smaller than 100 mesh. The iron ore powder and CaO reagent are mixed in a mass ratio of 1:0.38 to form a binary basicity mixture of 2.0, and the sintering reinforcing agent is finally obtained. The mass fraction of the sintering reinforcing agent finally obtained in Example 3 is shown in Table 1.

[0056] Example 4

[0057] A method for preparing sintering strengthening agents using high-speed railway steel slag, the specific process flow is as follows:

[0058] ① In the converter smelting production process, after the converter slag is discharged, the converter steel slag is treated by hot quenching and hot pouring. The converter slag then enters the magnetic separation line for magnetic separation to obtain magnetic separation tailings. The main chemical components of the magnetic separation tailings are TFe: 20%, CaO: 50%, SiO2: 15%, and MgO: 9%.

[0059] ② Grind the magnetic separation tailings obtained in step ① to make the particle size less than 100 mesh. Place the magnetic separation tailings in an acidic solution (acetic acid solution) with a concentration of 1 mol / L, wherein the solid-liquid ratio of the magnetic separation tailings to the acetic acid solution is 1:5 g / mL, the reaction temperature is 20℃, the reaction time is 2h, and the stirring speed is 300 rpm. After filtration, leachate and leaching tailings are obtained. The main chemical components of the leaching tailings are TFe: 25%, CaO: 26%, SiO2: 30%, and MgO: 6%.

[0060] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe their melting morphology. The measured melting point was 1201℃.

[0061] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe the melting morphology. The melting rate was measured to be 106 s.

[0062] ③ Add an acidic solution (hydrochloric acid solution) to the leaching tailings obtained in step ②. The concentration of the hydrochloric acid solution is 2 mol / L, and the solid-liquid ratio of the leaching tailings to the hydrochloric acid solution is 1:5 g / mL. The reaction temperature is 20℃, the reaction time is 2h, the stirring speed is 300 rpm, and the mixed solution reacts for a period of time. After the solid and liquid layers separate, filter and dry to obtain the sintering strengthening agent masterbatch.

[0063] ④ The dried reinforcing agent masterbatch (iron ore powder) and reinforcing regulator (CaO) obtained in step ③ are ground into powders smaller than 100 mesh. The iron ore powder and CaO reagent are mixed in a mass ratio of 1:0.38 to form a binary basicity mixture of 2.0, and the sintering reinforcing agent is finally obtained. The mass fraction of the sintering reinforcing agent finally obtained in Example 4 is shown in Table 1.

[0064] Example 5

[0065] A method for preparing sintering strengthening agents using high-speed railway steel slag, the specific process flow is as follows:

[0066] ① In the converter smelting production process, after the converter slag is discharged, the converter steel slag is treated by hot quenching and hot pouring. The converter slag then enters the magnetic separation line for magnetic separation to obtain magnetic separation tailings. The main chemical components of the magnetic separation tailings are TFe: 20%, CaO: 50%, SiO2: 15%, and MgO: 9%.

[0067] ② Grind the magnetic separation tailings obtained in step ① to make the particle size less than 100 mesh. Place the magnetic separation tailings in an acidic solution (acetic acid solution) with a concentration of 1 mol / L, wherein the solid-liquid ratio of the magnetic separation tailings to the acetic acid solution is 1:5 g / mL, the reaction temperature is 20℃, the reaction time is 2h, and the stirring speed is 300 rpm. After filtration, leachate and leaching tailings are obtained. The main chemical components of the leaching tailings are TFe: 23%, CaO: 27%, SiO2: 30%, and MgO: 5% by mass.

[0068] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe their melting morphology. The measured melting point was 1201℃.

[0069] The leaching tailings obtained in step ② were molded into cylindrical materials with a diameter and height of 3 mm. The materials were then fed into a heating device to observe the melting morphology. The melting rate was measured to be 106 s.

[0070] ③ Add an acidic solution (hydrochloric acid solution) to the leaching tailings obtained in step ②. The concentration of the hydrochloric acid solution is 1 mol / L, and the solid-liquid ratio of the leaching tailings to the hydrochloric acid solution is 1:10 g / mL. The reaction temperature is 20℃, the reaction time is 2h, the stirring speed is 300 rpm, and the mixed solution reacts for a period of time. After the solid and liquid layers separate, filter and dry to obtain the sintering strengthening agent masterbatch.

[0071] ④ The dried reinforcing agent masterbatch (iron ore powder) and reinforcing regulator (CaO) obtained in step ③ are ground into powders smaller than 100 mesh. The iron ore powder and CaO reagent are mixed in a mass ratio of 1:0.38 to form a binary basicity mixture of 2.0, and the sintering reinforcing agent is finally obtained. The mass fraction of the final sintering reinforcing agent obtained in Example 5 is shown in Table 1.

[0072] Table 1. Comparison of the mass fraction (wt%) of sintering strengthening agent and magnetic separation tailings obtained in Examples 1-5

[0073] Group TFe CaO SiO2 MgO Magnetic separation tailings 20 50 15 9 Example 1 44 29 11 3 Example 2 40 25 13 4 Example 3 32 30 14 7 Example 4 36 32 13 6 Example 5 39 31 14 5

[0074] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention, or equivalent embodiments can be modified based on the disclosed technical content, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. A method for preparing a sintering strengthening agent using high-speed railway steel slag, characterized in that, The method includes the following steps: ① The converter steel slag is treated by hot quenching, hot pouring, shallow pan quenching, air quenching or water quenching and then subjected to magnetic separation to obtain magnetic separation tailings; the main chemical components of the magnetic separation tailings are TFe: 15% ~ 25%, CaO: 40% ~ 60%, SiO2: 10% ~ 20%, MgO: 6% ~ 10% by mass fraction; ② Grind the magnetic separation tailings obtained in step ①, leach them in an acidic solution, and filter to obtain leachate and leach tailings; The acidic solution in step ② is a solution prepared from one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, ammonium chloride, ammonium nitrate, and ammonium sulfate, with a concentration of 0.5~2 mol / L and a pH value of 2~3; the solid-liquid ratio of the magnetic separation tailings to the acidic solution is 1:5~1:40 g / mL; the leaching temperature is 10℃~100℃, the reaction time is 0.5~4h, and the leaching stirring rate is 150~600 rpm; the main chemical components of the leaching tailings are TFe: 20%~40%, CaO: 20%~30%, SiO2: 25%~35%, and MgO: 2%~6% by mass. ③ Add an acidic solution to the leaching tailings obtained in step ②, stir and react at 10℃~50℃ for 1~4h, filter and dry after solid-liquid separation to obtain sintering strengthening agent masterbatch; The acidic solution in step ③ is a solution prepared from one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, ammonium chloride, ammonium nitrate, and ammonium sulfate, with a pH value of 0.1~1 and a concentration of 0.5~1 mol / L; the solid-liquid ratio of the leaching tailings to the acidic solution is 1:5~1:40 g / mL, and the stirring speed is 300~600 rpm; ④ Grind the sintering strengthening agent masterbatch and strengthening regulator obtained in step ③ into powder, mix them in proportion, and prepare a mixture with a binary basicity of 1.5~3, which is the final sintering strengthening agent; The strengthening and regulating agent mentioned in step ④ is one or two of CaO reagent and SiO2 reagent. The dried strengthening agent masterbatch and strengthening and regulating agent are ground into powder with a mesh size of less than 100. The strengthening agent masterbatch and strengthening and regulating agent are mixed in a mass ratio of 1:0.25 to 1:0.5.

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